WF_BWP_SELECT_FILTER - Filtering Work Items

I have got a problem in understanding of the BADI WF_BWP_SELECT_FILTER. I want to filter all work items in our SRM system that are not relevant.

1. There will be always two debuggers opened when I set a break-point in the BADI implementation class! Does anybody know why?

2. Is it possible to filter work items with a status that is not 'READY'? There are many items with another status that should not be in the inbox of the SRM user. These items will not be passed through the BADI.

3. Does anybody know where I can find an overview about the possible task (like TS14508044)?.